Evaluation of insecticides against aphid vectors of virus diseases of French bean.
Field trials were conducted during rabi seasons of 2002-03 and 2003-04 in Jharkhand, India, to evaluate insecticides against aphid vectors of virus diseases of French bean cv. Selection-9. The lowest Bean common mosaic virus (BCMV) disease incidence of 15.8% and 14.4% was recorded in case of two sprays of monocrotophos at 1 ml/litre of water during 2002-03 and 2003-04, respectively. This treatment also gave lowest disease incidence of Bean yellow mosaic virus (BYMV). The highest seed yield of 12.05 q/ha and 11.70 q/ha with per rupee return of Rs. 14.86 and 9.58 was also recorded with monocrotophos. Next to monocrotophos, two sprays of dimethoate at 1 ml/litre recorded 16.6% and 18.0% disease incidence of BCMV, 19.4% and 22.5% of BYMV and seed yield of 10.75 and 11.2 q/ha and per rupee return of Rs. 13.34 and 10.01, respectively. Among neem-based insecticides, two sprays of Achook at 5 ml/litre was superior to Horse power at 2 ml/litre and Neem guard at 2 ml/litre. Achook sprays recorded BCMV disease incidence of 20.3% and 19.6%, BYMV disease incidence of 20.4% and 23.4% during 2002-03 and 2003-04, respectively, with 9.85 and 10.90 q/ha seed yield and per rupee return of Rs. 4.88 and 4.37 during the two crop seasons.